This invention relates to the destruction of hazardous waste materials, particularly, to a method and apparatus for conversion of hazardous waste material into useful by-products.
The safe disposal of hazardous waste materials is a high priority for both private industry and governmental agencies. A superfund has been established by the government to clean up areas of hazardous waste which present eminent danger to the public health and welfare. Thousands of regulations have been promulgated by the government to insure the safe use and disposal of hazardous materials. Use of some hazardous materials has been banned or extremely restricted. Due to the severity of the problem, various methods have been utilized for disposing of hazardous materials. Research continues in an effort to develop a method for the destruction of hazardous material which is also environmentally safe.
Various methods have been attempted for the disposal of hazardous material, including the use of electric plasma arcs to destroy toxic waste. Plasma generators are known in the prior art. A plasma arc generated by a plasma gun develops an extremely hot temperature zone having temperatures in the range of 10,000.degree. F. to 30,000.degree. F., or above. At such high temperatures, almost all organic and inorganic compounds may be converted into useful by-products.
U.S. Pat. No. 4,644,877 discloses a method and apparatus for the pyroelectric destruction of toxic or hazardous waste materials. The waste materials are fed into a plasma arc burner where they are atomized and ionized, and then discharged into a reaction chamber to be cooled and recombined into product gas and particulate matter. The recombined products are quenched using a spray ring attached to the reaction vessel. An alkaline atomized spray produced by the spray ring neutralizes the recombined products and wets the particulate matter. The product gases are then extracted from the recombining of products using a scrubber, and the product gases are then burned or used for fuel.
U.S. Pat. No. 4,479,443 discloses a method and apparatus for thermal decomposition of stable compounds. High temperatures necessary for decomposition are generated by a plasma generator. U.S. Pat. Nos. 4,438,706 and 4,509,434 disclose a procedure and equipment for destroying waste material. The material is decomposed in a plasma state in the presence of an oxidizing agent so that the waste material is converted into stable combustion products.
U.S. Pat. No. 4,615,285 discloses a method of destroying hazardous waste by means of under-stoichiometric incineration at a temperature of at least 1,200.degree. C. The ratio between injected waste material and oxidant is regulated to give a quotient CO.sub.2 /(CO.times.CO.sub.2) of less than 0.1.
U.S. Pat. Nos. 4,602,991 and 4,729,891, by the Applicant herein disclose a coal liquefaction process and hydrogen generating method, respectively, wherein the feed stock is heated in an inductive furnace under vacuum conditions.
As is noted above, various methods have been tried for disposing of hazardous waste material. Until the present invention, however, a commercially viable process which combines vacuum, induction and plasma technology for conversion of hazardous materials into useful by-products has not been available.